Conventionally, when performing a forging process, ultrasonic forging in which ultrasonic vibrations are applied to a die during forming is well known. For example, in ultrasonic forging described in, e.g., Patent Document 1 and Non-Patent Document 1, it is stated that application of ultrasonic vibrations can attain reduction of a forming load and improvement of a shape transfer property.
Such a forging device that performs ultrasonic forging is provided with a die, a vibrator attached to the die, and an ultrasonic oscillator that drives the vibrator, and is configured to apply ultrasonic vibrations to the die with the vibrator depending on the output of the ultrasonic oscillator.